"I was getting pushed from behind, I felt like, and by the time my spotter said lift or go low, it was too late," Larson said. "I was in the wreck and then felt like it was slowing down and I looked like I could see the ground. Had some flames come in the cockpit, but luckily I was all right and could get out of the car quick."

It appeared fans were lined right along the fence when Larson's car sailed up and into it, but Chitwood indicated there was a buffer. He said there would be no changes to the seating before the Daytona 500.

"We don't anticipate moving any of our fans," Chitwood said. "We had our safety protocols in place. Our security maintained a buffer that separates the fans from the fencing area. With the fencing being prepared tonight to our safety protocols, we expect to go racing tomorrow with no changes."

Larson's car appeared to hit where the cross-over gate - a section that can be opened for people to travel back and forth from the infield to the grandstands - is located in the fence. Previous accidents in which drivers hit crossover gates were severe, but the gates were in the wall and not the fence for Mike Harmon's accident at Bristol in 2002 and Michael Waltrip's at the same track in 1990.

Still, NASCAR senior vice president Steve O'Donnell said it would be studied.

"I think we look at this after every incident," O'Donnell said. "We've learned in the past certain protocols put in place today are a result of prior incidents. Again, our initial evaluation is still ongoing. But it's certainly something we'll look at. If we can improve upon it, we'll certainly put that in play as soon as we can."

Larson had been scheduled to race his sprint car later Saturday night in Ocala, Fla., and even seemed restless to get there during the late stages of the Nationwide race. He pulled out of the event following the accident.

"Honestly, the race itself pales in comparison to the injuries sustained by the fans," said Chip Ganassi, the team owner who has Larson in his driver development program. "Our thoughts and prayers go out to all the fans that were injured as a result of the crash. As for Kyle, I am very happy that he is OK."

Keselowski watched a replay of the final accident, and said his first thoughts were with the fans. As for the accident, he agreed he tried to make a winning move and Smith tried to block.

"He felt like that's what he had to do, and that's his right. The chaos comes with it," Keselowski said. "I made the move and he blocked it, and the two of us got together and started the chain events that caused that wreck. First and foremost, just want to make sure everyone in the stands is OK and we're thinking about them."

Keselowski said the incident could cast a pall on the Daytona 500.

"I think until we know exactly the statuses of everyone involved, it's hard to lock yourself into the 500," Keselowski said. "Hopefully, we'll know soon and hopefully everyone's OK. And if that's the case, we'll staring focusing on Sunday."